Posted
by
CmdrTacoon Wednesday July 20, 2011 @12:32PM
from the spinning-round-and-round dept.

thebchuckster writes "Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny, new satellite – temporarily designated P4 — was uncovered in a Hubble survey searching for rings around the dwarf planet. The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km)."

Hubble will eventually degrade in performance just as it has in the past. Gyros and batteries wear out, electronics get glitchy, etc.

Unfortunately, when it starts to happen again, there won't be anything we can do about it. Without the shuttle, another service mission is impossible. And with Hubble's successor (JWST) hanging by a fraying budgetary thread, there likely will be no replacing it with an improved telescope, either.

We as a country have given up on science, unless it makes immediate profits for megacorporations or helps the military kill people more efficiently in foreign lands.

Unfortunately, when it starts to happen again, there won't be anything we can do about it. Without the shuttle, another service mission is impossible. And with Hubble's successor (JWST) hanging by a fraying budgetary thread, there likely will be no replacing it with an improved telescope, either.

This has been repeated a number of times, but launching an entirely new Hubble into high orbit (without a shuttle, that is) would be substantially cheaper than maintaining the shuttle program in order to service the existing scope. I hope JWST pulls through, but I don't think NASA should get a blank check from the taxpayers.

We as a country have given up on science, unless it makes immediate profits for megacorporations or helps the military kill people more efficiently in foreign lands.

I'm not a fan of our budget priorities for the last decade, but I can understand why Congress is viewing JWST skeptically. The telescope isn't even supposed to launch until 2017 at the earliest and it's already billions of dollars over budget. Sure, this is a fraction of what we're flushing down the toilet in futile wars, but we're already stuck in those, and they're much more difficult to pull out of than a project that's still in the planning stages.

Except for servicing Hubble - a dubious justification - the shuttle was a terribly inefficient use of money for the science that came out of the program. As far as scientific funding in general is concerned, NASA continues to do great work with remote probes and will be sending another rover to Mars soon. The NIH and NSF managed to avoid major funding cuts in a year when most federal agencies got hit hard, and the DOE Office of Science, which was slated for a huge cut, also survived mostly intact. Speaking as a scientist involved with many of these agencies, I'm thrilled with the outcome.

We as a country have given up on science, unless it makes immediate profits for megacorporations

I'm not thinking Hubble was manufactured by schoolchildren or launched by a volunteer group.

That's the mystifying part. You'd think there's just as much room for corruption in the aerospace contracting field as the banking field, but apparently fraud is easier in the banking industry. Since they (as in the big bankers) are not going to let us fix the banking system, the solution would seem to be, make the aerospace industry as corrupt, or more corrupt, than the banking industry.

We as a country have given up on science, unless it makes immediate profits for megacorporations or helps the military kill people more efficiently in foreign lands.

What's more disappointing is that the other industrialized countries haven't taken this torch and run with it. Europe has at least 50% more population than the USA, and a larger economy (and it appears, stronger, despite the problems in Greece). While obviously no one country there can match the US in size and economic power, combined they eas

The USA economy is the largest of any single country in the world. The entire EU beat us very narrowly with 1.5x the number of people.Remember this when people start talking about "lazy Americans". We're producing nearly as much as 1.5x the number of Europeans are.

US citizens are quick to claim that the US isn't this, or the US isn't that. Fact of the matter is we are still the shit.

We have the highest GDP of any country, we have the highest standard of living, and have the highest rate of scientific advanc

Wrong. Sweden, Norway, and Switzerland consistently lead the standard-of-living rankings worldwide. USA is way down on the list. Having the "highest standard of living" doesn't mean your richest people live the most opulent lifestyles, it means your average people live the safest, most comfortable, and most healthy lifestyles. If you want to compare the rich peoples' lifestyles, then places like Mexico would rank high on the list, since the world's richest man, Carl

Those "jobs a trained monkey can do" will always orders of magnitude more plentiful than the jobs that require a college education. This means that the pay rates going to those workers will do far more to the economy than the budgets of a few engineers and scientists. This attitude that pay rate should be mostly determined by level of education will eventually destroy any economy that buys into it. I don't care how much a country develops, no population can be sustained on primarily higher education jobs.

I live in the US too, and it looks like we're falling apart to me with ever more corporate corruption in government.

The US has one of the best-educated populations in the world

You've got to be kidding. Every ranking shows our public education to be near the bottom of industrialized countries. Sure, if you compare our education to Zimbabwe's or Myanmar's, we look pretty good, but that's not saying much.

Actually, it is (along with Eris, Makemake, Ceres, Quaoar and many others, mostly with technical identifiers) properly termed a dwarf planet. Not a planet, a dwarf planet. So the article is actually quite correct.

I spent my entire childhood thinking pluto was a planet. To me it will always be a planet. Even my 9yo was originally taught it was a planet. Where's the love? Seriously, after 76 years, NOW you're going to choose to call it a 'dwarf planet'? I think not.

If you have enough gravity to have something orbiting you, then you get to be a planet.

There's got to be an 'in soviet russia' joke here, I'm just not sure what it is yet.

While the official definition that made Pluto no longer a planet does not include this, I know I have seen various discussions justifying Pluto's dwarf planet status by pointing out that the center of mass for Pluto and its natural satellites is outside the solid part of Pluto itself. So what I have wondered today with this article is this: Does the new moon change that fact and move the center of mass back to Pluto proper?

You make it too complicated. Here are the criteria:1. It is not on fire (sun)2. It has something not man made orbiting it.3. It was discovered before 19314. It's larger than the smallest listed in #2 (this will pick up mercury which otherwise would have failed my tests.

The criteria used by everyone else is:1. a celestial body orbiting a star or stellar remnant2. massive enough to be rounded by it's own gravity3. not massive enough to be in a state of thermonuclear fusion (which would make it a star)4. has cleared the neighboring region of planetesimals

Not likely. Eventually its all found. Like arguing we must redefine australia as an island, or else we'll have trillions of "continents" in the ocean. Eventually you find them all. For example, we are not likely to find any new planets within the orbit of Mars.

and there will be an insoluble argument about where you draw the line between planets and asteroids,

Easy Peasy. Does it crush itself under its own mass to an almost spherical shape? Theoretical compression stress at the core due to gravity exceeds stress limit of the rock? Then its a planet. An asteroid is a smaller lump of rock that isn't h

There's tons of tiny asteroids with their own, even smaller, moons. Are we going to call those planets too? Do we need to have schoolchildren remember the names of hundreds of moon-bearing asteroids, I mean planets?

The good news is the names are pretty easy. Whats the planet orbiting between Kepler-11 B and Kepler-11 D? Oh let me guess it's Kepler-11 C.

What happens when they find a new planet between them? Rename everything farther away, leading to questions like "did you mean the object named Kepler-11 C before [date], or the object named that after [date]?"

Interstate exit numbers suffered this same issue every time a new exit was built, by the way, which is why they all got renumbered after the corresponding mile ma

I thought there were still some stupid states that hadn't done that, or are you saying the last holdouts (I'm thinking PA was one) finally changing their exit numbering?

They haven't changed them here in CT or in nearby NY yet. There are, however gaps in the numbers sometimes...not sure if it's because the exits were removed, planned but never made, or someone didn't know how to count. For example, the first exit on I-95 in CT is exit 2.

Honestly, I can't imagine why anyone would prefer sequential exit numbering. I don't care how many exits exist between my and my destination, I only care about the absolute distance. Numbering them with mile numbers also makes it easy to calculate how far different exits are from one another (suppose you have two destinations to visit in your trip, one at exit 217 and one at exit 219; that's two miles between them, versus exit 138 and exit 159, where it's 21 miles).

Let's be consistent:Only satellites that have been pulled into a spherical shape by their mass and have cleared their orbit around the planet should be called "moons". The rest are obviously "dwarf moons".

As for what we should call a satellite that orbits a satellite, I vote for "Zappa".

I assume you mean "if I have consistent standards..." since that seems to be the most common argument.

It boils down to how many planets do you want to have in the solar system. Most honest attempts at a scientific definition that includes Pluto also include a handful of other known bodies. That's fine, 8 planets, 9 planets, 14 planets... who cares right? The problem is that modern theory predicts dozens of Pluto-like bodies in the outer solar system, and having 70+ planets listed is seen as extremely awk

It boils down to how many planets do you want to have in the solar system. Most honest attempts at a scientific definition that includes Pluto also include a handful of other known bodies. That's fine, 8 planets, 9 planets, 14 planets... who cares right? The problem is that modern theory predicts dozens of Pluto-like bodies in the outer solar system, and having 70+ planets listed is seen as extremely awkward, especially when only a handful of them would be scientifically interesting as individual bodies (as opposed to a class of bodies like the predicted objects in the outer Oort cloud would be).

Fair enough, but why should we want an arbitrary upper bound on the number of planets? Awkwardness isn't really an issue except for elementary school kids memorizing lists; we have these things called "computers" now that are remarkably good at keeping track of large amounts of information. If there are a bunch of planets floating around out there in the dim outer reaches of the Solar System, fine -- we'll get to them we develop the technology to make it possible. And I don't see why they should be any l

What I've always found peculiar regarding the definition used to demote Pluto is that by that very definition, Neptune should be a non-planet as well, seeing as it hasn't "cleared" it's orbital path either.

If you calculate the ratio of the mass of the object to the mass of all the other objects in the same orbit, there is a vast difference between the planets and the dwarf planets. The eight planets have ratios on the order of 10^4 through 10^6, meaning they are much, much more massive than everything else in their orbit combined. The dwarf planets, including Pluto, all have ratios less than one.

But ratios aren't in the definition. From the wikipedia article:
"...a planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has 'cleared its neighbourhood' of smaller objects around its orbit."
These three criteria define a planet and Pluto definitely meets the first two. As for the last, Pluto's perihelion is inside Neptune's orbit, thus (in my humble opinion) still clutters Neptune's orbital neighborhood.
I think the definition should have been chosen so a

"Cleared the neigbourhood" has a specific meaning. It means that the object has become gravitationally dominant, and there are no other bodies of comparable size other than its own satellites or those otherwise under its gravitational influence. Pluto is in a resonant orbit with Neptune. In other words, Pluto falls into the "those otherwise under its gravitational influence" category. If you want an absolutely clear orbit, the even Jupiter fails. Basically, every planet has co-orbitting asteroids.

But "Mass large enough to compress it into a sphere." depends upon what the object is made of, and where it is. Ice will form a sphere at a lower gravity than rock. A rocky body close to the Sun may be more pliable than an equally massive hunk of ice in the outer rim territories. Thus a lower gravitational pull would be needed to round it out.

All orbiting objects orbit around a non-fixed barycenter. The only factors determining if that center is inside or outside one of the planets is the ratio of masses of an object pair, the distance between them and the radius of the more massive object.

Pluto and Charon orbit around a non-fixed barycenter that is actually outside of both Pluto and Charon. Pluto/Charon is really a binary Dwarf Planet with 3 moons. Which, honestly, is fucking awesome.

Absolutely! Further more its physical and orbital characteristics clearly associate it with the recently discovered Kuiper Belt Objects. It is should not be viewed as a "pathetic little planet wannabe" but as the King of the KBOs (Eris would be the Queen).

So the space station is a moon? And the hammer they dropped up there? And Saturn's rings are moons too?

I would be good with a definition of moon that requires a spherical shape and long-term stable orbits. That would exclude Mars' satellites, which is fine with me. They're just captured asteroids in decaying orbits.

Yep. I'm pretty comfortable with the idea that our star holds on to more than nine planets. I also think the idea that Pluto isn't a planet is ridiculous, and that any definition that ends up that way is by definition, busted.

But if you stop counting Pluto as a planet, and then you discover another Kuiper Belt object that's not only bigger than Eris but as big or bigger than Mercury, do you make it a planet, or do you take Mercury off the list? Right now, the IAU definition of planet is deliberately limited to our own solar system, just so it doesn't apply to situations extra-solar astronomers have actually already found, or are very likely to find in the next few years (How do you determine wh

"Right now, the IAU definition of planet is deliberately limited to our own solar system, just so it doesn't apply to situations extra-solar astronomers have actually already found,"

AFAIK "extra-solar astronomers" are not members of the IAU and are probably not aware that the IAU even exists. Maybe when the news of Pluto's demotion reaches them (which will take a while since there don't seem to be any habitable planets within a few LY of the sun) they could send the IAU a message about it. Of course all ali

Not only that, but as a definition it is empirical and not subjective, like the various "size" based definitions are.

Planet: Any body which has all of the following properties:1. It's mass has compressed it into a spherical shape.2. It's primary orbit is around a star3. It has cleared it's orbit of all other bodies that aren't satellites of itself, Lagrange point bodies, or "twin" satellites of similar mass that it stably co-orbits with where the co-orbital point exists outside either body.

> 3. It has cleared it's orbit of all other bodies that aren't satellites of itself, Lagrange point bodies, or "twin" satellites of similar mass that it stably co-orbits with where the co-orbital point exists outside either body.

Wouldn't this definition preclude a Kemplerer Rosette? Sure, they don't occur in nature, and are in fact quite unstable without active stationkeeping, but if you put (to pick a number at random) 5 Earth-sized planets equally spaced in the same orbit, be kinda silly to declare th

You missed the "Stable" part of the definition. Any body not in a stable orbit, regardless of size, would not be considered a "planet".

Yes, it may seem silly, but a randomly wandering body, regardless of size, shouldn't be called a planet. I think "Planetoid" or "dark body" would be more accurate, although we may need to come up with a new word.

However the size alone should not be the definitional point as size-based parameters are constantly subject to revision, and are thus unreliable.

The trick there is, whatever we declare the worlds of an artificial rosette to be, what they are is whatever the transhuman species that made them calls them. Trust me - you don't want to get into an argument with people who can shoot you with a gun that causes your grandparents to have a 50 year string of bad luck, precluding you ever being born. Whether they call them "planets", "properly sorted and indexed lebensraum", or "the big round closets where I keep all my stuff when I'm back in this brane", we'd

I include it as it not only allows BOTH Pluto and Charon to be counted as planets, but also takes into account any new extra-solar co-orbiters we may discover in the future.

Except that they haven't in fact cleared their orbit of all other bodies that aren't satellites - with the discovery of the Kuiper Belt, Pluto started looking a lot more like Ceres than it did like Mercury.

Your definition comes very close to having the moon declared a planet. Although at present the barycenter is below the surface of the Earth, the moon is constantly moving away from the Earth. The day will come when, by your definition, the moon will suddenly and instantly be elevated to planet-hood even though nothing obvious has changed.

Not that that makes your definition wrong of course, just pointing it out.

The argument of what is and isn't a planet is older than people realize; Isaac Asimov suggested

Your definition comes very close to having the moon declared a planet. Although at present the barycenter is below the surface of the Earth, the moon is constantly moving away from the Earth. The day will come when, by your definition, the moon will suddenly and instantly be elevated to planet-hood even though nothing obvious has changed.

Not that that makes your definition wrong of course, just pointing it out.

Excellent point. However I would hasten to point out that I included several other definitional points that must all be met to call a body a planet. Certainly point number 4 about having enough gravitational force to hold onto an atmosphere would prevent Luna from being classified as a new planet as it escapes Earth's grasp.

It amounts to people having a holy war over where blue ends and purple begins. It's arbitrary. They needed a definition and it was generally felt that a definition that kept the number of planets to a reasonable number was in everyone's interest. The reason the definition was changed was because modern theory predicts dozens or even hundreds of Pluto-like objects in the outer solar system, which was thought to be an unreasonable number of bodies to be labeled as planets.

Seeing that the declaration that Pluto wasn't a planet was a failure on it's part (not intentionally, I'm sure) to meet a good standard for a planet (as designed by astrophysics), the 'flip of the coin' idea must be presented by someone who still hold out hope that Pluto would attain the status it once had. Do not let his attempt at subterfuge confuse you; instead of 'solving the craziness' he's only attempting to extending it for another chance at winning.

We shall now call an object in solar orbit, a Solar Orbiting Object. Size will be a secondary classification, with descriptive terms like Large (LaSOO), Medium (MeSOO) and Small (SmaSOO). If it is the object has cleared its orbit, it is the primary object of that orbit, so we have Primary (Pri) and Shared (Sha). Under this system, Pluto is a ShaSmaSOO and Jupiter is a PriLaSOO.

For the objects that orbit a SOO, it is a SOOOO, a Solar Orbiting Object Orbiting Object. Prim

But the point is, the number of satellites should have nothing to do with whether a body is classified as a planet or not, because it's not logically connected to the classification. It's pretty intuitive that two planets of the same size could gobble up different numbers of smaller satellites on a pretty much random basis. We don't want to make a random factor paramount in defining something. That bit about clearing orbits in the standard definition the IAU now uses... Isn't that an es